As semiconductor technology develops, a type of electronic cards so-called smart card has been applied widely in various areas of daily life. For example, smart cards may be utilized as an electronic wallet, so that people may not need to carry large amount of money for shopping. In addition, as an example, smart cards may also be utilized as the required tickets when people are travelling by public transports, such that the required waiting-time for purchasing tickets may be reduced significantly, and meanwhile, the time waste caused by inspecting tickets manually may also be reduced.
Smart cards with more functions have also been proposed with the increasing popularization of smart cards. Thus, some of smart cards are required a built-in battery, in order to provide the power when the smart card is implementing a particular function. However, in the prior art, when the electricity of the battery in a smart card is completely consumed, the user must replace the currently used smart card. In other words, the user is possibly required to replace the used smart card regularly, thereby causing the usage inconvenience of electronic cards.